1. Field of the Invention
The present invention relates to a liquid transfer device and a liquid transfer head for transferring conductive liquid.
2. Description of Related Art
Conventionally, as printing devices for printing on a medium to be printed, such as a paper, for example, inkjet heads of various types are known for ejecting ink onto a paper or the like. For example, JP-A-2003-326712 discloses an inkjet head including a passage unit and a piezoelectric actuator unit. The passage unit has therein a plurality of individual ink flow passages each of which includes a pressure chamber connected to a nozzle. The actuator unit is for applying pressure to ink in the respective pressure chambers of the passage unit. In general, the piezoelectric actuator unit has a plurality of individual electrodes corresponding to the respective pressure chambers connected to the nozzles; a common electrode opposed to the plurality of individual electrodes; and a piezoelectric layer made of lead zirconate titanate (PZT), sandwiched by the individual electrodes and the common electrode. When the electric potential of an individual electrode is controlled to be different from that of the common electrode, an electric field is applied to the portion of the piezoelectric layer sandwiched by the individual electrode and the common electrode and thereby the piezoelectric layer is partially deformed. By the deformation of the piezoelectric layer, pressure is applied to the ink in the corresponding pressure chamber. Thus, ink is ejected through the nozzle connected to the pressure chamber.
In the above-described inkjet head, the plurality of individual ink flow passages each including a nozzle and a pressure chamber, are formed in the passage unit, and the actuator unit having the plurality of individual electrodes, the common electrode, and the piezoelectric layer, is disposed on a surface of the passage unit. Therefore, the construction of the inkjet head is considerably complicated, and this brings about an increase in the manufacturing cost. In addition, each pressure chamber must have a certain volume or more for ejecting a desired amount of ink. As a result, in the case that a large number of nozzles and a large number of pressure chambers are required to be formed in an inkjet head, however, it is difficult that a plurality of individual ink flow passages including the respective nozzles and pressure chambers are densely formed in a passage unit. That is, reduction in size of the inkjet head is difficult.